Passiflora cutting

Hi
I'm looking for some advice on how to manage a passiflora cutting. The two pics attached show the cutting in the early stages as it began to root and grow leaves and the second is where we are at 5 months on.
On average it is growing about 8cm a month which I'm really pleased about but all the growth is currently coming on one long trailing branch off the main stem which as you can see by the first picture is very thin and potentially weak.
Over time will the stem thicken up?
Come the end of summer I've been told to cut the growing branch back to no more than a foot in length. is this wise? Will it not just shock the plant and kill it?
How do I get it to sprout branches in other places so that it isn't just one long trailing arm?
My aim is to be able to plant this in the garden a year from now once it has toughened up and looks like it could withstand life out doors.
Any advice that anyone can offer would be greatly received as I know next to nothing about how to care for developing cuttings like these and especially pasiflora.
Thanks
P
Posts
That's correct, chop it down, there's no point in having one long weak stem, if you cut it off it will thicken out from the bottom next year.
If it were mine I'd do now, give the roots system time to strengthen before winter.
As I found out Philippa ? Mind you, the flowers are stunning every year despite a really hard chop every Spring. (Or probably because of)
Thank you both for your advice I guess it's just a case of being brace and cutting it back in the next couple of weeks and letting the roots continue to develop.
Will it be possible to save the piece that's cut off and get it to root line this one did or is it too young and fragile to work?
Looks a bit fragile but you've nothing to lose so give it a try.
are you sure you want two???
Only really because the plant has sentimental value ? If all goes well my answer 2 years from now I may be asking how do I control these things!!!